Motorized spindle assembly and numerical control machine tool

Abstract

The application provides an electric spindle assembly and a numerical control machine tool. The electric spindle assembly comprises a shaft core, a bearing, an encoder spacer ring and a cylinder connecting disc, which are sequentially installed on the first shaft section in the direction away from the second shaft section, and the second shaft section is in contact with the inner ring of the bearing; the cylinder connecting disc comprises a first mounting hole and a second mounting hole which are sequentially communicated in the direction away from the encoder spacer ring, the hole diameter of the first mounting hole is smaller than the hole diameter of the second mounting hole, and the first mounting hole is in plug-in cooperation with the first shaft section; an encoder gear is sleeved on the cylinder connecting disc and is fixedly connected with the cylinder connecting disc to rotate synchronously with the shaft core; and a locking nut is arranged in the second mounting hole and is sleeved on the first shaft section to be threadedly connected with the shaft core, so that the problem that the code disc of the encoder installed on the electric spindle is easily inclined in position and affects the accuracy of the signal of the encoder in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of numerical control machine tools, in particular to an electric spindle assembly and a numerical control machine tool. BACKGROUND

[0002] At present, the electric spindle is a structure that combines the spindle motor and the machine tool spindle into one in the field of intelligent equipment numerical control machine tools, and the electric spindle also integrates lubrication, cooling, encoder, tool changing and other functions, compared with the mechanical spindle, the electric spindle has the advantages of compact structure, small vibration and noise, stable machining performance and high machining precision, and the high-precision numerical control machine tool has high requirements for the installation of the encoder inside the electric spindle, both the axial detection distance of the encoder and the inclination between the gear of the encoder and the shaft core need to be ensured.

[0003] The electric spindle of the lathe in the prior art usually installs the gear of the encoder on the shaft core, and presses it tightly through the oil cylinder connecting disc and the locking nut at the rear end, and the electric spindle of the lathe needs to change the workpiece when machining the workpiece, generally uses the oil cylinder as the driving mechanism to perform the action of changing the workpiece, and the oil cylinder connecting disc will be impacted during the driving process of the oil cylinder, and the long-time impact will cause the oil cylinder connecting disc to loosen, thereby causing the encoder gear to tilt, the phase angle to be lost, and finally the signal detection of the encoder to fail. Therefore, in order to ensure the detection accuracy of the encoder, the installation of the encoder gear needs to be axially and radially limited.

[0004] For this, there is also a device for fixing the encoder disc of the electric spindle in the prior art, the disc in the device is arranged on the shaft core and located between the shaft shoulder and the baffle of the shaft core, a plurality of tight screws are installed in the circumferential direction of the baffle to top on the disc, the end of the baffle away from the disc is in contact with the shaft core, and the contact position is provided with a shaft steel wire retainer, which is convenient to install and remove, but the shaft steel wire retainer is easy to fail under stress, and once it fails, the encoder disc is easy to tilt, which will affect the signal of the encoder. SUMMARY

[0005] The main purpose of the present application is to provide an electric spindle assembly and a numerical control machine tool, so as to solve the problem that the disc of the encoder installed on the electric spindle in the prior art is easy to tilt in position and affect the accuracy of the signal of the encoder.

[0006] In order to achieve the above object, according to one aspect of the present application, an electric spindle assembly is provided, comprising: a spindle core, the spindle core comprising a first spindle segment and a second spindle segment connected in sequence, an outer diameter of the first spindle segment being smaller than an outer diameter of the second spindle segment; a bearing, an encoder spacer ring and a cylinder connecting disc, the bearing, the encoder spacer ring and the cylinder connecting disc being installed on the first spindle segment in sequence in a direction away from the second spindle segment, the second spindle segment being in contact with an inner ring of the bearing; the cylinder connecting disc comprising a first mounting hole and a second mounting hole communicated in sequence in a direction away from the encoder spacer ring, a hole diameter of the first mounting hole being smaller than a hole diameter of the second mounting hole, the first mounting hole being used for plug-in cooperation with the first spindle segment; an encoder gear, the encoder gear being sleeved on the cylinder connecting disc and located at an end of the cylinder connecting disc close to the encoder spacer ring, the encoder gear being fixedly connected with the cylinder connecting disc to rotate synchronously with the spindle core; a locking nut, the locking nut being arranged in the second mounting hole and sleeved on an end of the first spindle segment away from the second spindle segment, the locking nut being threadedly connected with the spindle core.

[0007] Further, the electric spindle assembly comprises a rear end cover, the rear end cover being arranged in the second mounting hole, the rear end cover being installed on a side of the first spindle segment away from the second spindle segment and abutting against a side of the locking nut away from the cylinder connecting disc.

[0008] Further, the rear end cover and the spindle core are connected through a plurality of first fasteners, the rear end cover is provided with a plurality of first countersunk holes for one-to-one corresponding installation of the plurality of first fasteners, and the spindle core is provided with a plurality of first threaded holes threadedly connected with the plurality of first fasteners one-to-one corresponding.

[0009] Further, the electric spindle assembly further comprises a plurality of jackscrews, the rear end cover is provided with a plurality of third threaded holes for one-to-one corresponding installation of the plurality of jackscrews, and the locking nut is provided with a plurality of abutting holes abutting against the plurality of jackscrews one-to-one corresponding.

[0010] Further, the rear end cover comprises a cover main body and a limiting protrusion arranged on a side of the cover main body close to the locking nut for abutting against the locking nut, and the cover main body and the limiting protrusion jointly enclose an avoiding groove for avoiding the spindle core.

[0011] Further, the limiting protrusion is an annular protrusion; or the limiting protrusion comprises a plurality of protruding portions arranged in sequence and spaced apart around an axis of the spindle core.

[0012] Further, the spindle core and the cylinder connecting disc are connected through a flat key, the first spindle segment is provided with a first key groove, the first mounting hole is provided with a second key groove, a part of the flat key is located in the first key groove, and another part of the flat key is located in the second key groove.

[0013] Further, the oil cylinder connecting disc comprises a third shaft segment and a fourth shaft segment connected in sequence in a direction away from the encoder spacer ring, an outer diameter of the third shaft segment is smaller than an outer diameter of the fourth shaft segment, and the encoder gear is mounted on the third shaft segment, and the fourth shaft segment is in contact with an end surface of the encoder gear.

[0014] Further, the fourth shaft segment and the encoder gear are connected through a plurality of second fasteners, a plurality of second countersunk holes for mounting the plurality of second fasteners one by one are arranged on the fourth shaft segment, and a plurality of second threaded holes threadedly connected with the plurality of second fasteners one by one are arranged on the encoder gear.

[0015] According to another aspect of the present application, a numerical control machine tool is provided, comprising the above-mentioned electric spindle assembly.

[0016] According to the technical scheme of the present application, the electric spindle assembly comprises: a shaft core, the shaft core comprises a first shaft segment and a second shaft segment connected in sequence, an outer diameter of the first shaft segment is smaller than an outer diameter of the second shaft segment; a bearing, an encoder spacer ring and an oil cylinder connecting disc, the bearing, the encoder spacer ring and the oil cylinder connecting disc are mounted on the first shaft segment in sequence in a direction away from the second shaft segment, and the second shaft segment is in contact with an inner ring of the bearing; the oil cylinder connecting disc comprises a first mounting hole and a second mounting hole connected in sequence in a direction away from the encoder spacer ring, a hole diameter of the first mounting hole is smaller than a hole diameter of the second mounting hole, and the first mounting hole is used for plug-in cooperation with the first shaft segment; an encoder gear, the encoder gear is sleeved on the oil cylinder connecting disc and located at an end of the oil cylinder connecting disc close to the encoder spacer ring, the encoder gear is fixedly connected with the oil cylinder connecting disc to rotate synchronously with the shaft core; and a locking nut, the locking nut is arranged in the second mounting hole and sleeved on an end of the first shaft segment away from the second shaft segment, and the locking nut is threadedly connected with the shaft core. In this way, the electric spindle assembly limits the axial movement of the bearing, the encoder spacer ring and the oil cylinder connecting disc relative to the first shaft segment through the locking nut and the second shaft segment, avoids the axial movement of the oil cylinder connecting disc and the encoder gear relative to the first shaft segment, solves the problem that the code disc of the encoder installed on the electric spindle is easy to be inclined in position to affect the accuracy of the signal of the encoder in the prior art, and ensures the reliability and stability of the installation of the encoder gear. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. In the drawings:

[0018] Figure 1 A sectional view of an embodiment of the electric spindle assembly according to the present application is shown;

[0019] Figure 2 A sectional view of an embodiment of the electric spindle assembly according to the present application is shown; Figure 1The sectional view is partially enlarged at A.

[0020] Figure 3 The partial structural diagram of the shaft core of the electric spindle assembly is shown. Figure 1 The partial structural diagram of the shaft core of the electric spindle assembly is shown.

[0021] Figure 4 The partial structural diagram of the shaft core of the electric spindle assembly is shown. Figure 1 The partial structural diagram of the shaft core of the electric spindle assembly is shown.

[0022] Figure 5 The partial structural diagram of the shaft core of the electric spindle assembly is shown. Figure 1 The partial structural diagram of the shaft core of the electric spindle assembly is shown.

[0023] Figure 6 The partial structural diagram of the shaft core of the electric spindle assembly is shown. Figure 1 The partial structural diagram of the shaft core of the electric spindle assembly is shown.

[0024] Figure 7 The partial structural diagram of the shaft core of the electric spindle assembly is shown. Figure 1 The partial structural diagram of the shaft core of the electric spindle assembly is shown.

[0025] Among them, the above-mentioned drawings include the following reference signs:

[0026] 1, shaft core; 101, first threaded hole; 102, first key groove; 11, first shaft segment; 12, second shaft segment;

[0027] 2, bearing;

[0028] 3, encoder spacer ring;

[0029] 4, encoder gear; 401, second threaded hole;

[0030] 5, flat key;

[0031] 6, cylinder connecting disc; 601, second countersunk hole; 602, second key groove; 61, first mounting hole; 62, second mounting hole; 63, third shaft segment; 64, fourth shaft segment;

[0032] 7, locking nut; 701, abutting hole;

[0033] 8, cover; 81, cover body; 82, limiting protrusion; 83, avoiding groove; 801, first countersunk hole; 802, third threaded hole. DETAILED DESCRIPTION

[0034] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0035] As Figures 1 to 7As shown, the present application provides an electric spindle assembly, comprising: a shaft core 1, the shaft core 1 comprising a first shaft section 11 and a second shaft section 12 connected in sequence, the outer diameter of the first shaft section 11 being smaller than the outer diameter of the second shaft section 12; a bearing 2, an encoder spacer ring 3 and a cylinder connecting disc 6, the bearing 2, the encoder spacer ring 3 and the cylinder connecting disc 6 being installed on the first shaft section 11 in sequence in a direction away from the second shaft section 12, the second shaft section 12 being in contact with the inner ring of the bearing 2; the cylinder connecting disc 6 comprising a first mounting hole 61 and a second mounting hole 62 communicated in sequence in a direction away from the encoder spacer ring 3, the hole diameter of the first mounting hole 61 being smaller than the hole diameter of the second mounting hole 62, the first mounting hole 61 being used for plug-in cooperation with the first shaft section 11; an encoder gear 4, the encoder gear 4 being sleeved on the cylinder connecting disc 6 and located at one end of the cylinder connecting disc 6 close to the encoder spacer ring 3, the encoder gear 4 being fixedly connected with the cylinder connecting disc 6 to rotate synchronously with the shaft core 1; a locking nut 7, the locking nut 7 being arranged in the second mounting hole 62 and sleeved on one end of the first shaft section 11 away from the second shaft section 12, the locking nut 7 being threadedly connected with the shaft core 1.

[0036] In this way, the electric spindle assembly of the present application limits the axial movement of the bearing 2, the encoder spacer ring 3 and the cylinder connecting disc 6 on the first shaft section 11 relative to the first shaft section 11 through the locking nut 7 and the second shaft section 12, avoids the axial movement of the cylinder connecting disc 6 and the encoder gear 4 on the cylinder connecting disc 6 relative to the first shaft section 11, solves the problem that the code disc of the encoder installed on the electric spindle in the prior art is easy to be inclined in position and affect the accuracy of the signal of the encoder, and ensures the reliability and stability of the installation of the encoder gear.

[0037] Specifically, the end of the first shaft section 11 away from the second shaft section 12 is provided with an external thread for threadedly connecting with the internal thread on the locking nut 7.

[0038] As shown in Figure 1 , the electric spindle assembly comprises a rear end cover 8, the rear end cover 8 being arranged in the second mounting hole 62, the rear end cover 8 being installed on the side of the first shaft section 11 away from the second shaft section 12 and abutting against the side of the locking nut 7 away from the cylinder connecting disc 6.

[0039] As shown in Figures 1 to 3 and Figure 7 , the rear end cover 8 and the shaft core 1 are connected through a plurality of first fasteners, the rear end cover 8 is provided with a plurality of first countersunk holes 801 for one-to-one corresponding installation of the plurality of first fasteners, and the shaft core 1 is provided with a plurality of first threaded holes 101 threadedly connected with the plurality of first fasteners one-to-one corresponding.

[0040] The plurality of first countersunk holes 801 are uniformly arranged around the axis of the shaft core 1 by 360 degrees, the plurality of first threaded holes 101 are also uniformly arranged around the axis of the shaft core 1 by 360 degrees, each first fastener is a screw, the nut end of each first fastener is inserted into the corresponding first countersunk hole 801, and the threaded end of each first fastener is screwed into the corresponding first threaded hole 101 after passing through the corresponding first countersunk hole 801.

[0041] As shown in Figure 1 and Figure 2 and Figure 6 and Figure 7 The electric spindle assembly further comprises a plurality of jackscrews, the rear end cover 8 is provided with a plurality of third threaded holes 802 for one-to-one corresponding installation of the plurality of jackscrews, and the locking nut 7 is provided with a plurality of abutting holes 701 for one-to-one corresponding abutment of the plurality of jackscrews.

[0042] The plurality of third threaded holes 802 are uniformly arranged around the axis of the shaft core 1 by 360 degrees, the plurality of abutting holes 701 are also uniformly arranged around the axis of the shaft core 1 by 360 degrees, the threaded section of each jackscrew (i.e. a set screw) is inserted into and threadedly connected with the corresponding third threaded hole 802, and the jacking end of each second fastener is abutted in the corresponding abutting hole 701 after passing through the corresponding third threaded hole 802.

[0043] As shown in Figure 2 The rear end cover 8 comprises a cover body 81 and a limiting protrusion 82 provided on the side of the cover body 81 close to the locking nut 7 for abutting with the locking nut 7, and the cover body 81 and the limiting protrusion 82 jointly enclose an avoiding recess 83 for avoiding the shaft core 1.

[0044] Optionally, the limiting protrusion 82 is an annular protrusion; or the limiting protrusion 82 comprises a plurality of protruding portions sequentially and spacedly arranged around the axis of the shaft core 1.

[0045] Thus, the lock nut 7 is mounted on the first shaft section 11 of the shaft core 1, the end face of the side of the lock nut 7 away from the second shaft section 12 is flush with the end face of the side of the first shaft section 11 away from the second shaft section 12; the rear end cover 8 is detachably connected between the side of the lock nut 7 away from the second shaft section 12 and the shaft core 1 through a plurality of first fasteners, the avoiding groove 83 of the rear end cover 8 is used for avoiding the end of the first shaft section 11, so that the limiting protrusion 82 of the side of the rear end cover 8 close to the lock nut 7 abuts against the lock nut 7, so as to limit the axial movement of the lock nut 7 relative to the first shaft section 11, so as to play a first anti-loosening effect on the lock nut 7; the jackscrew tightened in the third threaded hole 802 on the rear end cover 8 abuts against the abutting hole 701 on the lock nut 7, so as to further limit the axial movement of the lock nut 7 relative to the first shaft section 11, so as to play a second anti-loosening effect on the lock nut 7, thereby strengthening the axial limiting effect of the cylinder connecting disc 6 and the encoder gear 4. In addition, the rear end cover 8 of the present application also has the advantages of simple structure, low processing cost, reliable use and convenient installation and disassembly.

[0046] As shown in Figures 1 to 3 and Figure 5 , the shaft core 1 and the cylinder connecting disc 6 are connected through the flat key 5, the first key groove 102 is arranged on the first shaft section 11, the second key groove 602 is arranged in the first mounting hole 61, the first key groove 102 and the second key groove 602 are oppositely arranged, a part of the flat key 5 is located in the first key groove 102, and the other part of the flat key 5 is located in the second key groove 602, so as to limit the circumferential movement of the cylinder connecting disc 6 relative to the shaft core 1 through the flat key 5, limit the circumferential movement of the encoder gear 4 relative to the shaft core 1, and ensure that the encoder gear 4 and the cylinder connecting disc 6 can rotate synchronously with the shaft core 1, thereby ensuring that the encoder does not lose phase angle during signal transmission.

[0047] As shown in Figure 4 and Figure 5 , the cylinder connecting disc 6 comprises a third shaft section 63 and a fourth shaft section 64 connected in sequence away from the encoder spacer ring 3, the outer diameter of the third shaft section 63 is smaller than the outer diameter of the fourth shaft section 64, the encoder gear 4 is mounted on the third shaft section 63, and the fourth shaft section 64 is in contact with the end face of the encoder gear 4.

[0048] Specifically, the fourth shaft section 64 and the encoder gear 4 are connected through a plurality of second fasteners, the fourth shaft section 64 is provided with a plurality of second countersunk holes 601 for one-to-one mounting of the plurality of second fasteners, and the encoder gear 4 is provided with a plurality of second threaded holes 401 threadedly connected one-to-one with the plurality of second fasteners.

[0049] The plurality of second countersunk holes 601 are uniformly arranged around the axis of the shaft core 1 by 360 degrees, the plurality of second threaded holes 401 are also uniformly arranged around the axis of the shaft core 1 by 360 degrees, each second fastener is a screw, the nut end of each second fastener is inserted into the corresponding second countersunk hole 601, and the threaded end of each second fastener is screwed into the corresponding second threaded hole 401 after passing through the corresponding second countersunk hole 601.

[0050] The application further provides a numerical control machine tool comprising the electric spindle assembly.

[0051] From the above description, it can be seen that the above-mentioned embodiments of the application achieve the following technical effects:

[0052] The electric spindle assembly of the application comprises: a shaft core 1, the shaft core 1 comprises a first shaft segment 11 and a second shaft segment 12 connected in sequence, the outer diameter of the first shaft segment 11 is smaller than the outer diameter of the second shaft segment 12; a bearing 2, an encoder spacer ring 3 and a cylinder connecting disc 6, the bearing 2, the encoder spacer ring 3 and the cylinder connecting disc 6 are sequentially installed on the first shaft segment 11 in a direction away from the second shaft segment 12, and the second shaft segment 12 is in contact with the inner ring of the bearing 2; the cylinder connecting disc 6 comprises a first mounting hole 61 and a second mounting hole 62 sequentially communicated in a direction away from the encoder spacer ring 3, the hole diameter of the first mounting hole 61 is smaller than the hole diameter of the second mounting hole 62, and the first mounting hole 61 is used for plug-in cooperation with the first shaft segment 11; an encoder gear 4, the encoder gear 4 is sleeved on the cylinder connecting disc 6 and located at one end of the cylinder connecting disc 6 close to the encoder spacer ring 3, and the encoder gear 4 is fixedly connected with the cylinder connecting disc 6 to rotate synchronously with the shaft core 1; a locking nut 7, the locking nut 7 is arranged in the second mounting hole 62 and sleeved on one end of the first shaft segment 11 away from the second shaft segment 12, and the locking nut 7 is threadedly connected with the shaft core 1. In this way, the electric spindle assembly of the application limits the axial movement of the bearing 2, the encoder spacer ring 3 and the cylinder connecting disc 6 on the first shaft segment 11 relative to the first shaft segment 11 through the locking nut 7 and the second shaft segment 12, avoids the axial movement of the cylinder connecting disc 6 and the encoder gear 4 on the cylinder connecting disc 6 relative to the first shaft segment 11, solves the problem that the code disc of the encoder installed on the electric spindle is easy to be inclined in position and affects the accuracy of the signal of the encoder in the prior art, and ensures the reliability and stability of the installation of the encoder gear.

[0053] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0054] The recitation of ranges of values herein are merely intended to serve as a method of discussion of certain examples. Unless otherwise stated, the scope of the present application is not to be limited to specific relative positions, numerical expressions, and values set forth in these embodiments. Also, it is to be understood that the dimensions shown in the various portions illustrated in the drawings are not drawn to scale. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail because such techniques, methods, and apparatus are well known. In all examples shown and discussed herein, any specific values are to be interpreted as merely exemplary and not limiting. Other examples of the exemplary embodiments can have different values. It is to be noted that like numbers and letters refer to like elements throughout the several views of the drawings and that the illustrated drawing figures are not necessarily to scale.

[0055] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "up", "down", "left", "right", "lateral", "vertical", "horizontal", "top", "bottom", and the like are generally based on the orientation or positional relationships shown in the drawings, and are merely intended to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the components themselves.

[0056] For the convenience of description, spatial relative terms such as "above", "upper", "top", "up", and the like can be used herein to describe the spatial relationship of one device or feature to another device or feature as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations of the devices in use or operation in addition to the orientation of the devices described in the drawings. For example, if the devices in the drawings are inverted, the device described as "above" or "above" the other device or structure will be positioned "below" or "below" the other device or structure. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0057] In addition, it should be noted that the use of the terms "first", "second", and the like do not have a special meaning and are used only to distinguish corresponding parts, and therefore cannot be construed as limiting the scope of protection of the present application.

[0058] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. An electric spindle assembly, characterized by, The electric spindle assembly comprises a shaft core (1), a bearing (2), an encoder spacer ring (3), an oil cylinder connecting disc (6), an encoder gear (4) and a locking nut (7). The shaft core (1) comprises a first shaft section (11) and a second shaft section (12) connected in sequence, wherein the outer diameter of the first shaft section (11) is smaller than the outer diameter of the second shaft section (12). The bearing (2), the encoder spacer ring (3) and the oil cylinder connecting disc (6) are sequentially mounted on the first shaft section (11) in a direction away from the second shaft section (12), and the second shaft section (12) is in contact with the inner ring of the bearing (2). The oil cylinder connecting disc (6) comprises a first mounting hole (61) and a second mounting hole (62) sequentially communicated in a direction away from the encoder spacer ring (3), wherein the hole diameter of the first mounting hole (61) is smaller than the hole diameter of the second mounting hole (62), and the first mounting hole (61) is used for plug-in cooperation with the first shaft section (11). The encoder gear (4) is sleeved on the oil cylinder connecting disc (6) and located at one end of the oil cylinder connecting disc (6) close to the encoder spacer ring (3), and the encoder gear (4) is fixedly connected with the oil cylinder connecting disc (6) to rotate synchronously with the shaft core (1).

2. The electric spindle assembly according to claim 1, characterized in that, The locking nut (7) is arranged in the second mounting hole (62) and sleeved on one end of the first shaft section (11) away from the second shaft section (12), and the locking nut (7) is threadedly connected with the shaft core (1).

3. The electric spindle assembly according to claim 2, characterized in that, The electric spindle assembly comprises a rear end cover (8) arranged in the second mounting hole (62), wherein the rear end cover (8) is mounted on one side of the first shaft section (11) away from the second shaft section (12) and abuts against one side of the locking nut (7) away from the oil cylinder connecting disc (6).

4. The electric spindle assembly of claim 2, wherein, The rear end cover (8) and the shaft core (1) are connected by a plurality of first fasteners, the rear end cover (8) is provided with a plurality of first countersunk holes (801) for one-to-one corresponding mounting of the plurality of first fasteners, and the shaft core (1) is provided with a plurality of first threaded holes (101) threadedly connected with the plurality of first fasteners one-to-one corresponding.

5. The electric spindle assembly of claim 2, wherein, The electric spindle assembly further comprises a plurality of jackscrews, the rear end cover (8) is provided with a plurality of third threaded holes (802) for one-to-one corresponding mounting of the plurality of jackscrews, and the locking nut (7) is provided with a plurality of abutting holes (701) abutting against the plurality of jackscrews one-to-one corresponding. The rear end cover (8) comprises a cover body (81) and a limiting protrusion (82) arranged on one side of the cover body (81) close to the locking nut (7) for abutting against the locking nut (7), and the cover body (81) and the limiting protrusion (82) jointly enclose an avoiding groove (83) for avoiding the shaft core (1).

6. The electric spindle assembly according to claim 5, wherein The limiting protrusion (82) is an annular protrusion; or The limiting protrusions (82) comprise a plurality of protruding portions arranged in sequence and spaced around the axis of the shaft core (1).

7. The electric spindle assembly of claim 1, wherein, The shaft core (1) and the oil cylinder connecting disc (6) are connected through a flat key (5), the first shaft section (11) is provided with a first key groove (102), the first mounting hole (61) is provided with a second key groove (602), a part of the flat key (5) is located in the first key groove (102), and the other part of the flat key (5) is located in the second key groove (602).

8. The electric spindle assembly of claim 1, wherein, The oil cylinder connecting disc (6) comprises a third shaft section (63) and a fourth shaft section (64) connected in sequence away from the encoder spacer ring (3), the outer diameter of the third shaft section (63) is smaller than that of the fourth shaft section (64), the encoder gear (4) is mounted on the third shaft section (63), and the fourth shaft section (64) is in contact with the end face of the encoder gear (4).

9. The electric spindle assembly according to claim 8, characterized in that, The fourth shaft section (64) and the encoder gear (4) are connected through a plurality of second fasteners, the fourth shaft section (64) is provided with a plurality of second countersunk holes (601) for one-to-one mounting of the plurality of second fasteners, and the encoder gear (4) is provided with a plurality of second threaded holes (401) threadedly connected with the plurality of second fasteners one-to-one.

10. A numerically controlled machine tool, characterized by comprising: An electric spindle assembly comprising any one of claims 1 to 9. An electric spindle assembly comprising any one of claims 1 to 9.

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